Shock absorber



Nw. 22 X932. w. R. GRlswoLD SHOCK ABSORBER Filed Deo; 6, 1950 me/nio@ NHL TER R. E'RzsNaLn.

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Patented Nov.. 22, 1932 UNITED swl'las PATENT oFFlca WALTI'B B. GRIBWOLD, OF DETROIT, MICHIGAN, ASSIGNOR T0 PACKARD MOTOR COMPANY, F DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN i HOCX .LBSORBEB Application med December 6, 1980. Serial No. 500.585.

-This invention relates to shock absorbers and more particularly to shock absorbers of the hydraulic type,

Hydraulic shock absorbers depend for their absorbing qualities upon the resistance set up in a chamber to the movement of a piston forcing duid through restricted openings. The rate of iiuid How through an opening depends upon viscosity and it is evident that the resistance to piston movement is materially inuenced by variations in viscosity thereby resulting in a varying action of the shock absorber in accordance with temperature.

ln order to compensate for the varying viscosity oi' the duid in the shock absorbers, it has been proposed to provide a manual adjustinent for regulating the size of the relief openings but such adjustment must be made too often to meet temperature conditions in the usual climates ii uniform riding qualities in a motor vehicle are to be maintained. It has also been proposed to supply the-shock absorber with a prepared duid which wiil operate over a long temperature range without an appreciable change in viscosity7 but such fluids are expensive and are not satisfactory over a temperature range extending through 'all and spring in average climatic conditionsv Furthermore, with either of the L' above described systems, uniform riding;

qualities are not present because even in the coldesiJ weather with the shock absorber in constant and violent action, the temperature oi the duid fluctuates suciently to materially vary the viscosity thereof.

The variation oi? the manual adjustment is often inconvenient and always an objectionu able taslr so that it is ordinarily neglected, and an automobile is driven with shock absorbers having an action which is too hard or too soit. Such conditions are apt to result in -brolren springs or uncomfortable riding ouiaiities .fin object oi this invention resides in the y rovision oit a shock absorber device of the hydraulic type in which the action is in iduenced by viscosity variations of the working fluid em loyed.

Another object of the' invention is to provide a hydraulic shock absorber in which variation in the' viscosity of the working fluid is compensated for automaticall A further object of my invention is to provide a hydraulic shock absorber in which the viscosity of the working fluid influences a flow control valve to compensate for variations caused by temperature so that a uniform action results under all climatic conditions.

Other objects of the invention will appear from the following description taken in connection with the drawing,|which form a part of this specification, and in which:

Fig. l is a sectional view of a shock absorber embodying the invention;

Fig. 2 is another sectional view taken on line 2--2 of Fig. 1;

Fig. 3 is a sectional view taken on line` 3-3 of Fig. 2. l

Referring to the drawing by characters of reference, represents a casing structure for a hydraulic shock absorber which is adapted to be fixed to an element of a motor vehicle. This casing is provided with a transversely extending end Wall 11 from which a hub portion 12 extends and a bearing 13 extends through and is carried by the end wall and the hub extension. 'Extending' through the bearing is a shaft 1li upon which is hired an arm 15, such arm being associated with an element of the motor vehicle mova- "ble relative to the element to which the casing 10 is ixed., A packing 16 surrounds the shaft at the outer end of the bearing and is held in position by the nut i7.

Another casing 18 is telescopically associated with the casing 10 and is provided with a recessed end wall. 19 which encloses the casing 1() and forms therewith a chamber 20 in which a vane type of piston 21, :formed as an integral part of the shaft 14, operates. The recessed portion of the casing 18 provides a chamber 22 which opens through the end wall 19, and a cover 23 encoses'the end of the'casing 18 and-engages the end thereof' Y The recess 22 and the'space between the 10@ l' cover 23 Iand the o casing wall 19 provide a reservoir for the working duid which can be returned to the working chamber 20 through the passage 26 formed toA extend in an axial direction in the shaft and o ening into the reservoir at its inner end. onnecting with the passage 26 isr another passage 27 which extends perpendicularly thereto through the piston or vane 21 and ports 28 connect the passage 27 with the working chamber on osite sides of the piston. One-way va ves 29 are interposed in each of the passages 28 andstop members 30 are arranged i to the other under pressure of the piston or 4 lsleeve member valve member is independent d of the dow between the valve member and` its vane 21 in its movement.

A sleeve valve member 311 is screwed into the casing 10 so that one end thereof lies adjacent an end of the passage 33, and the space dened thereby determines the rate of travel of the working fluid between the grooves 31. Arkey member 35 is associated with the end of the sleeve valve 3a to regulate its position relative tc its seat and a nut 36 is provided to retain the key member in desired adjusted position. linteriorly of the 34 is a one-way valve 37 which permits additional dow` of working fluid between the grooves 31 through valve ports and this auxiliary passageway through the of the control seat.

Movement of the vane 21, through turning of the shaft 1d, will compress the working duid in one side of the working chamber and vforce the working duid through the groove 31 on such side and through the passages 32 and 33, and through'the other grooves 31 to the o posite side of the working chamberf lln this manner/the working duid is moved back and forth from one side of the piston to the other through the grooves 31 and the passages 32 and 33. rli`he flow is restricted by the valve 34, and in this manner the resistance to the vane movement',- can be increased or diminished so that a softer orharder ride will result. Working duid is drawn from the reservoinformed by the recess 22 and the cover 23, through the passages 26 and 27, and through the ports 28 into the working chamber, it being understood that the flow of duid will move into the suction side of the chamber depending upon the vane movement andin this manner a uniform Aquantity of the working duid is maintained in the operating "the Ishock absorber so far described forms aeaaaao the subject matter of applications Serial Nos. 293,125 and 366,975, filed July 16, 1928 and May 29,11929 respectively, by Alfred Moorhouse, and lis one type of shock absorber with which my invention, which l am scribe, can be associated.

llt will be seen that flow of the working fiuid from one side ofthe piston to the'other in the Working chamber varies with temperature becauseof the resultant change of viscosity and the fixed position of the fiow controlling valve. lt is a purpose of this invention to automatically compensate for the change in the rate of duid flow, caused by varylng temperature, in 'a shock absorber through mechanism directly responsive to the viscosity of the working uid.

To this end il provide the shaft 14 with an axially extending recess 6 0 having diverging passages 61 extending therefrom through the shaft on opposite sldes of the vane 21 for shunting the working fluid in the chamber so that it will not be required to travel in its regular path. A valve 62 projects into the recess 60 for controlling the flow through the passages 61, and is formed witha circularly extending recess 63. The valve is also formed with a. helical thread 6ft which engages the shaft so that the valve can move axially relative to the shaft.4 0

A vane 65 is arranged in the reservoir and is fixed to therein, while a by the pin 67, to the flat coiled spring 66 is xed forms a flexible driving connection between the valve and the shaft. The s ring is of such a nature that it acts normal y to screw the valveto its innermost position inthe recess, and when in such position the recess 63 will be beyond the ports 61 so that the valve will prevent flow of the working iiuid therethrough. When the viscosity of the working duid, which is preferably a form of oil, is low the resistance thereof to movement of the vane 65 with the shaft 14: is not sufficient to overcome the spring' tension and consequently the lvalve will rotate with the shaft and will thus prevent any How of the working fluid through the ports 61. When vthe viscosity of the working fluid inthe reservoir is caused 4to rise to `a predetermined extent by temperature conditions, sistance is offered to the rotation of the vane 65 with the shaft 14, and under such circumstances the vane will not move as shaft la which will cause screwed axially. This axial the valve depends upon the viscosity of working fluid and when the viscosity is high enough the recess 63 will be moved to a position where it will establish communication between the orts 61 and permit flow of the working-fluid from one side of the vane 21 to the other in the working chamber, and in movement of about to de-l shaft and is fixed tothe projecting end of the valve. This spring,

the end of the valve which pro'ects then greater refast as the the valve 62 to bev the i that it is relieved from travel around the grooves 31 and the passages 32 and 33. The tension of the spring will determine the viscosity at which the valve is moved to a position Where this shunting action will start, and the shunting can be arranged for so that regardless of the viscosity of the working fluid the resistance to the' oscillation of the Y vane 2l Will be substantially the same under Y all temperature conditions.

It will be seen that with the viscosity control described, a shock absorber can be provided Which Will have a uniform action under any temperature condition, and consequently no adjustment has to be made for different temperature conditions.

1While I have herein described in some detail a specific embodiment of my invention, which I deem to be new and advantageous and may specifically claim, I do not desire it to be understood that my invention is limited to the exact details of the construction, as it will be apparent thatchanges may be made therein Without departing from the spirit or scope of my invention.

What I claim is:

1. In a hydraulic shock absorber, a casing containing fluid, a piston in the casing, valve means controlling the flow of fluid from one Vto the other side. of the piston during operation thereof, g and means responsive to the viscosity of the fluid for regulating the valve j means.

2. InI a hydraulic shock absorber,a casing having a chamber containing fluid, a piston in the casing chamber, duct means through which fluid travels from one side of the chamber to the other under pressure caused by the piston movement, said piston having a passage-through which fluid passes from one side of the piston to the other in the-chamber, a valve for regulatingithe fluid flow. through lthe passage-.in the piston'and means actuated by the fluid in accordance with the viscositythreof for regulating the valve.

3. In a hydraulic shock absorber, a casing having a fluid containing chamber, a movable piston in the casing chamber, duct means in the casing through which fluid is forced from one side of the chamber to' the other, another duct means through which fluid can travel from one side of the chamber to the other, valve means in the last mentioned duct means, and means responsive to the viscosity of the fluid for automatically regulating the valve to maintain a uniform piston action under all temperature conditions.

4. In a hydraulic shock absorber, a casing having a fluid containing working chamber', a piston in the chamber-,fluid in the'chamber movable from one position to another by the piston, means regulating the lrate of fluid movement, and means actuated by the fluid in accordance with the viscosity thereof for controlling said fluid regulating means.

the piston to the other, and automatic mechanism partly in the reservoir for regulating the valve, said mechanism being responsive to the viscosity of the fluid in the reservoir.

7. In a hydraulic shock absorber, a casing containing a working chamber and a reser- Voir, a piston in the chamber, means includinga valve for controlling fluid flow from one side of the chamber toanother in response to the piston action, a vane in the reservoir for regulating the valve position, and a resilient connection between the valve and the piston.

8. In a hydraulic shock absorber, a casing containing a Working chamber and a reservoir, fluid in the chamber and reservoir, a piston in the chamber having a shaft projecting into the reservoir. said piston shaft having a passage terminating on opposite sides of the piston in the chamber, a valve for regulating fluid flow through the passage, a vane in the reservoir fixed to the Valve, and a resilient connection between the valve and the piston shaft, said connection normally urging the valve into position closing the passage.

9. In a hydraulic shock absorber, a casing containing a working chamber and a reservoir, fluid in the chamber and the reservoir, an oscillating piston in the chamber having a shaft projecting into the reservoir, said shaft having apassage therethrough opening on opposite sides of the piston in the casing, a valve extending' axially through one end of the shaft and helically threaded therein, said valve-extending into the reservoir and movable axially to control fluid through the assage in the shaft, a vane in the reservoir fied to the valve, and a spring connection between the shaft and the valve opposing relative rotation of the shaft and valve. j

10. In a hydraulic shock absorber, a casing containing a working chamber, fluid in the i chamber, a piston in thechamber, said casing having a passage connecting the chamber on o posite sides of the iston, means for permittmg the shunting o Huid from one side of the chamber to the other to maintain a uniform piston action under varying degrees of the fluid viscosity, and means actuated by the fluid in accordance `with the viscosity thereof for controlling said irst named means. i

12. ln ahydraulic shock absorber having a chamber containing Huid, meansfor moving the fluid from one position in the chamber to another, means for regulating the rate of fluid movement, and means actuated by the fluid in accordance with the viscosity thereof for controlling said regulating means.

13. ln a hydraulic shock absorber having a chamber containing Huid, means for moving the fluid from one position in the chamber to another, movable means for regulating the rate of movement, means actuated by the uidin accordance with the viscosity thereof for actuating said Huid regulating means,

^ and yieldable means resisting movement oil said Huid regulating means.

14. lin a hydraulic shock absorber, a casing having a Huid containing Working chamber and a fluid reservoir, a piston. in the chamber, means including a valve for controlling fluid flow from one side of the chamber to another in response lto the piston action, a'

Y vane in the reservoir for regulating the valve position, and a yieldable connection between the valve and the gisten l lin testimony w ereof ll alix my signature.

WALTER llt. GRlISWULD.

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